Tokyo Electric Power has revealed that 600 tons of radioactive reactor fuel melted during the disaster. Credit: Reuters

Fukushima clean-up teams are still unable to locate around 600 tons of melted radioactive fuel that leaked from three nuclear reactors, Tokyo Electric Power Company’s chief of decommissioning told the ABC’s Foreign Correspondent program in an exclusive interview.

Naohiro Masuda, said TEPCO hoped to pinpoint the exact location of the radioactive fuel and begin removing it from 2021, but he admitted the technology needed to remove the fuel still has to be invented.

“It’s estimated that approximately 200 tons of debris lies within each unit,” said TEPCO’s Naohiro Masuda.

“So in total, about 600 tons of melted debris fuel and a mixture of concrete and other metals are likely to be there.”

Fields of nuclear dirt and waste in plastic bags.

10 million bags of contaminated soil in gigantic waste dumps

Another supporter turned opponent of nuclear power is Naoto Kan, who was the Japanese prime minister at the time of the Fukushima meltdowns.

He says those who argue that nuclear power is a safe, cheap source of energy are misguided.

“So far, the government is paying $70 billion to support TEPCO,” Mr Kan said.

“But that is not enough. It will probably cost more than $240 billion. I think 40 years to decommission the plant is an optimistic view.”

More than 100,000 Japanese are still unable to return home because their communities lie in elevated radiation zones.